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RF Power Amplifiers

Mihai Albulet Noble Publishing 376 pages; $75 ISBN: 1-884932-12-6

The primary purpose of this book is to present the basic concepts used in the analysis and design of RF power amplifiers. Detailed mathematical derivations reveal the assumptions and limitations of the presented results, allowing readers to estimate their usefulness in practical applications. A good theoretical understanding is the quickest way toward achieving practical results. A designer must know a priori the circuit topologies and the basic operation principles, as well as limitations of the various amplification classes. Selecting the appropriate circuit topology and operating mode, knowing their pros and cons, and setting realistic goals for the expected performance are imperative for beginning a practical design.

The book covers the basics of the RF power amplifiers such as amplification classes, basic circuit topologies, bias circuits and matching networks. Chapter 1 discusses several basic concepts, terminology and definitions. Chapter 2 is dedicated to classic RF power amplifiers. Included are the oldest and best known classes of amplification: A, B, AB and C. Chapter 3 focuses on switching-mode class D amplifiers with some sections dealing with circuits operating in intermediate classes (BD and DE) or as frequency multipliers. Chapter 4 presents switching-mode class E amplifiers with additional sections describing amplitude modulation, class E frequency multipliers and computer simulation of this circuit. Chapter 5 is dedicated to class F amplifiers, including techniques to improve efficiency using harmonic injection in class B or C circuits. Chapter 6 comments on switching-mode class S amplifiers and modulators. Although these circuits are audio- or low frequency amplifiers, they are important subsystems in many high efficiency transmitters. Chapter 7 presents several considerations regarding bipolar and MOS RF power transistors.

This book is not a practical handbook for the design of power amplifiers but provides the reader with a thorough understanding of the concepts behind the different classes of amplifiers. Several examples are included in each chapter to illustrate these concepts.

Scattering of radar targets has become one of the most important parts of modern radar system analysis. Computer simulation of the radar targets' scattering is of great importance in the initial research and development steps of recognition, detection and tracking, and in modern radar education. Since aerial target orientation can be estimated only approximately, the statistics of scattered signals are more important than their exact values. This allows the wide use of scattering theory approximations.

Radar recognition development requires expensive experiments. The task of simulation in recognition is to replace such experiments in the initial R&D steps. Simulation programs can be used easily for detection and tracking.

The foundations of scattering simulation on centimeter and decimeter waves are described in Chapter 1. The review and simulation recognition features (signatures) for wideband and narrowband illumination of targets are the subjects of Chapters 2 and 3. In Chapter 4, the recognition algorithms' operation is reviewed and simulated. The peculiarity of backscattering simulation and recognition for low altitude targets is considered in Chapter 5. Chapter 6 offers the review and simulation of signals' detection and the operation of the simplest algorithms of target tracking. Chapter 7 attempts to expand the simulation possibilities for the case of targets with reduced cross section and covered with radar-absorbing materials and for the case of bi-static radar.

This is the first book on this topic to discuss all-around computer simulation of real targets' secondary radiation, primarily serving to solve recognition problems. Joint consideration of various recognition algorithms and their operation, which is absent in the most recent technical literature, may also be of interest.

This book is the result of extensive work by the group of authors, which are professors in military institutions in Kharkov, Ukraine and Minsk, Belarus. While an extensive bibliography is offered, 57 out of 152 references are in Russian.